When Parmitano and his partner, American Christopher Cassidy, parted ways to complete routine cable work during a spacewalk on July 16, Parmitano said he noticed feeling an "unexpected sensation of water" on the back of his neck. After informing NASA of the situation, Cassidy moves toward him to attempt to identify the water source.

"At first, we’re both convinced that it must be drinking water from my flask that has leaked out through the straw, or else it’s sweat. But I think the liquid is too cold to be sweat, and more importantly, I can feel it increasing. I can’t see any liquid coming out of the drinking water valve either," wrote Parmitano about his second spacewalk, his first one taking place a week earlier.

Houston decided to terminate the spacewalk, and both astronauts are directed to head to the airlock. While traveling back, Parmitano said the water level inside his helmet was increasing, compromising his ability to communicate and see. The water had covered the sponge on his earphones and the front of his visor. To make matters worse, Parmitano had to maneuver his way around an antenna along the route, requiring him to turn upside down into a vertical position, a move that resulted in water covering his nose. Because he did this as the sun was setting, what little vision he had disappeared and all he could see was blackness until entering the airlock again.

"By now, the upper part of the helmet is full of water and I can’t even be sure that the next time I breathe I will fill my lungs with air and not liquid," Parmitano wrote. He eventually reached the airlock and was able to feel his way inside. Cassidy joined him shortly after and once the area was repressurized, the crew was able to tend to Parmitano. NASA says between 1-1.5 liters of water leaked into his suit and helmet.

The spacewalk, which lasted an hour and 32 minutes, was the shortest one since 2004, when astronauts experiencing spacesuit problems walked for 14 minutes. Upon reflecting on the experience, Parmitano is reminded of the harsh realities of space, where a space suit puncture can result in immediate death. He concludes his post:

Space is a harsh, inhospitable frontier and we are explorers, not colonisers. The skills of our engineers and the technology surrounding us make things appear simple when they are not, and perhaps we forget this sometimes.